According to the criteria for classification of engineering rockmass and the actual stability state of mining preparation tunnels，the engineering quality of rock mass at –302 m sublevel of Chenchao Iron Mine is determined and evaluated by qualitative and quantitative methods. The engineering quality of rockmass at low sublevels is predicted furthermore. According to the different evaluation results，different reinforcing methods are selected. The evaluated and predicted results coincide well with practical cases，and the reinforcing methods are effective.

The finite element method based on DSC is introduced. The governing equations of the relative intact state and full-adjusted state and the equations of FEM are established. The solution schemes of the equations are given. The strain average method, the convergence and uniqueness of the finite element methods based on DSC are explained. The DSC model can allow well-posedness for localization and can avoid spurious mesh dependence. The laboratory test verifies the simulated results of the computational procedures. A number of research results show that the FEM based on DSC possess an altitude advantage over the classic computational procedures.

The failure process of notched specimens with pre-existed cracks or hard granules under external tensile loading are simulated with RFPA2D(Rock Failure Process Analysis)code. The influence of different heterogeneity on the coalescence of cracks and the load-displacement curve is analyzed. The simulating results indicate that it is the local stress concentration and deformation localization due to the heterogeneity that causes the complex interaction of cracks and different patterns of propagation and coalescence.

At first，a representative element is established theoretically for the orthotropic rockmass supported by systematic rock bolts. Then according to the concept of ‘equivalent material’ and under some simplified conditions，the constitutive expression and failure criterion for bolted rockmass are set up and introduced into 3D elasto-plastic FEM code. Through the calculation examples of an underground opening，the dynamic states of the surrounding rockmass with and without bolting are investigated，and some conclusions are given finally.

Based on understanding bolt-supporting mechanism，the simulation method is studied to analyse the deformation of bolt-supported rockmass by numerical manifold method. The method considers the effect of bolt on the strength of joints and stiffness of rockmass. An example is given and the result shows the method of simulating rock bolt is effective.

Based on the concept of equivalent stiffness of rock masses，the estimation of joint stiffness in distinct element model of stiff blocks is discussed. The propagation of P-wave in one-dimensional rock masses is analyzed according to plane to plane contact model. The P-wave shape is presented. The effects of damping，soft interlayer and tension property on the propagation characteristics are studied.

By using discrete element method，the simulation on an underground excavation iron mine is carried out and the displacement characteristic of the surrounding rockmass is obtained. Meanwhile a new way to determine the contacting parameters for discrete element analysis is presented.

The relation between the falling ability and damage of top coal is studied by damage mechanics. The model of damage parameter of top coal is found using meso-statistical damage mechanics. The damage parameter of top coal is regarded as the index of falling ability. Some factors，such as the mining depth，the strength of coal seam, initial crack and horizontal stress，which affect the falling ability of top coal，are discussed. The theoretical results are well agreeable with the experimental results.

The theoretical calculation model of the fragmentation size distribution containing damage variable is proposed. The average fragment size () and the percentage of undersize () are derived from the dynamic average fragmentation size formula of the fragile material given by Grady on the basis of fragmentation energy rules, fully considering the breaking action of the explosion stress wave and the motive fragment blocks extrusion and collision under the action of the detonation gas expansion and infiltration flow pressure. Some numerical simulations and verification tests are carried out. The results of numerical simulations coincide well with testing data. Simulations and tests show that the action of the extrusion and collision between motive fragment blocks is a significant factor affecting the average fragmentation size regardless the type of rock mass，especially for the rock mass with very bad quality. Some beneficial conclusions are summarized which are available for reference to practical projects.

A practical elastoplastic model for granular materials is proposed. The model can predict the stress-strain relation of granular materials in three-dimensional stresses，especially with confining-pressure dependency of strength and deformation. The model parameters can be converted from the parameters of the Duncan-Chang model. The model performance has been illustrated by comparing the model prediction results with the data of triaxial compression tests on rockfill material in the wide range of the confining-pressure.

Two-dimensional FEM，which can consider rheology of soil，is used to simulate the construction of excavation. Making use of this method，the rules of ground deformation in the bottom of foundation pit and round it are studied in details for different steps and different supporting conditions during excavation. The correlation between displacements and settlements behind supporting wall is also gained. The results can be used to consult in practice.

Bolt-grouting support is active method to combine bolt-spouting and grouting. In light of its support mechanism，a calculating model about its deformation is derived by means of action of bolt represented by volume-force and action of grouting regarded as improvement of properties of rock masses. The action of the support in preserving stability of surrounding rock masses is analyzed and its effect is proved being remarkable with using Kelvin-Voigt model and visco-elastic theory.

The middle-isolated pier is one of the key structures of permanent shiplock of the Three Gorges Project on Yangtze River，China. The rockmass deformation of middle-isolated pier of the second shiplock under various operation conditions is studied. The numerical simulations using 2-D distinct element method and 3-D finite element method are applied to analyze rockmass deformation law. Simultaneously，the time series analysis and grey system theory are used to predict the tendency of rock displacements based on in-situ measured data. The comprehensive results can be summarized as follows. (1) The horizontal displacement perpendicular to axial line of shiplock varies with process of excavation，and is in steady state after excavation. During operation of shiplock，the displacement is slightly decreased. (2) The horizontal displacement parallel to axial line of shiplock is of tendency of developing to downstream. (3) The vertical displacement occurred as resilient deformation during excavation，and then subsidence with slightly various values takes place in different part of the middle-isolated pier under different operation cases.

Tieshan tunnel of the Bapeng road is located in Daxiang of Shichuan province with the total length of 2 099 m. The tunnel passes through coal mined-out area K17-1，K21 and K24. The deformation，cracking，alteration and falling occur at the secondary lining at the station of K140+527～608 due to the influence of mined-out area，underground water and other factors，which do harm to the traffic safety，and must be cured. The stability of roof rocks of mined-out area is analysed according to engineering geological conditions and the reinforcement technology of mined-out area is presented.

By field observation in three longwall faces with different shallow overburden，the ground pressure behavior and the basic law of roof weighting are revealed. It is found that the strata breaking runs though whole roof，and there are big roof steps pushing in face during roof weighting. Shallow seam roof can not form stable roof block structure，and it will cause obvious roof pressure. It is also found that there are only two zones forming after strata collapse，the caving zone and the cracked zone. Speeding up face advancing is propitious to roof stability. Finally，the shallow seam definition for strata control is put forward by use of three key index，the key stratum，the thickness ratio of rock to soft overburden and the depth of coal seams.

Quantitative description for the evolution of crack in rock stratum is one of the fundamental problems of rock mechanics. Based on the field observation of the abutment pressure，the cracking process of top-coal is simulated. By using the fractal geometry，the evolution of crack is described quantitatively. It is found that the relation between the fractal dimension of crack and the abutment pressure is polynomial expression. According to the damage mechanics，the constitutive equations of the top-coal cracking is obtained.

With the help of theoretical analysis，numerical calculation and in-situ observations，the structure around the tailentry in soft rocks and its deformation and failure regularity in pillarless fully-mechanized sublevel caving are mainly introduced. The in-seam distressing entry layout is combined with concussion blasting technique，so that the tailentry in soft rocks can be effectively maintained. Meanwhile，the general distressing principle and practical distressing program are discussed. The theory and practice prove that this is a scientific strategy and an effective deci-sion-making to bring the tailentry in soft rocks under control.

A case-based reasoning approach to slope stability evaluation based on fuzzy analogy preferred ratio is presented，and a relative slope base case indexing model is set up. In this model，the fuzzy analogy preferred relationship between slope target case and slope base case is determined，and the similar series between the two cases with different affecting factor on slope stability is given. Determining the factor weights，the comprehensive similar series between the two cases is determined，and the most similar base case to the slope target case in the base cases of slope is found out. Finally，the slope stability of target case is evaluated. It is shown from examples that the result of stability evaluation of the slope is the same as the practical state，and the approach is simple，visual，practical，and convenient to use.

A new laboratory apparatus for coupled shear-flow of jointed rock was developed and used to investigate the coupled characteristic of a single rock fracture under shear and normal effective stresses. Based on shearing test of jointed marble sample under constant normal loads，the relationships among normal stress，shear stress，water pressure and flow quantity are presented, and the seepage charactristic of jointed rock is analysed. The relation equation between flow quantity and shear stress is deduced to fit the curves of testing data. By using an approximate regression equation，the relationship between the hydraulic conductivity and shear stress is estabilished eventually. The testing results reveal that the hydaulic conductivity of a sand-filled joint is reduced slightly with increasing shear stress，and the relationship between hydraulic conductivity and shear stress is linear approximately.

An explicit finite element method for dynamic analyses of fluid-saturated porous solid is derived on the basis of the classical Biot’s theory. The proposed method has the advantages of saving computer memory and saving computing effort over the conventional implicit methods. The proposed method can also efficiently treat the complex dynamic problem of fluid-saturated porous solid with nonlinear behavior or large degrees of freedom. To check the proposed explicit finite element method，two dynamic problems of fluid-saturated porous solid are solved. The numerical results agree well with the exact solutions.

Utilizing the dissipative structure theory，the evolutionary process of vibrating liquefaction in saturated granules is analyzed. When the irreversible force increases to some degree，the system will be in a state far from equilibrium，and the new structure probably occurs. According to synergetics，the equation of liquefaction evolution is deduced，and the evolutionary process is analyzed by dynamics. The evolutionary process of vibrating liquefaction is the process in which the period doubling accesses to chaos，and the fluctuation is the original driving force of system evolution. The liquefaction process is also analyzed by fractal geometry. The steady process of vibrating liquefaction obeys the scaling form，and shows self-organized criticality in the course of vibration. With the increment of the recurrence number，the stress of saturated granules will decrease rapidly or lose completely，and the strain will increase rapidly，so that the granules can not sustain load and the “avalanche” phenomenon takes place.

Water-burst passageway from coal floor results from the development and evolution of a series of small cracks. The renormalization group method is used to study the randomness and connectivity of the failture for coal floor element. On the basis，the critical character of water-burst from coal floor is analysed.

The stress-strain-volume change relationships and nonlinear strength behaviors of granular soils under high stresses are described. The limit pressure of spherical cavity expansion is given by the law of conservation, in which the volume change of spherical cavity is balanced with the compression of granular soil and the energy given out from spherical cavity expansion is absorbed by the volume change and shear strain caused in granular soil. This method can be used to estimate the penetration resistance of static cone penetration test and pile driving below the critical depth. The process of analysis shows that the limit pressure is determined by the characteristics of stress-strain-volume change relationships and strength of granular soil，and has no concern with the pressure of superstratum. The result shows that the calculating value of limit pressure has a few decreases under the influence of curved envelope and agrees well with the experiential data of the penetration resistance for medium dense sand.

Following the development of resources exploitation and engineering construction，the excavation depth is increased. The special mechanic character of surrounding rockmass in deep engineering appears and it is the challenge to the traditional theory. The current research state of surrounding rockmass character in deep engineering and design method is summarized and its developing tendency is put forward.

The probability distribution model of discontinuities is established through the three dimensional network modeling. A computational program applying the model is developed. With the program，all the finite rock blocks can be found out with free face exposed on excavation face. The geometrical parameters of the rock block are presented and the areas of the block faces together with the volume and center of block are calculated with this program.

The expressing method of synthesis knowledge by frame plus rule and neural network plus mathematics model is presented. Through corresponding transform，the expressing method will become reasoning rule. According to the possible modes of stabilization of gangue dam slope，the hardness degree of rock，joined state and development degree of structure surface，the character of flabbiness surface of dam bed，the fragmentation state of dam shoulder and seepage are considered. The illation and evaluation on the stability of the 2nd gangue dam in Dexing copper mine are made.

On the basis of Kelvin-solution，the analytical solution of influence coefficients of elastic analysis is achieved in indirect three-dimensional boundary element method based on FSM. The numerical initial system of the method is set up. For elastic analysis of large region，the calculating speed is faster and the precision is higher in comparision with tranditional BEM.

The search angle is an imporment factor to be considered to improve the prodiction distance and accuracy in the gedogical prodiction with TSP-202 seismic system. With the theory and method of probability，tectonic geology and material mechanics，the search angle obtained by TSP-202 seismic system is analysed. An adjustment method is proposed for the search angle to improve the prediction accuraey，and applied in Xinluona tunnel with good result.

The technique of sparklet-inboard-type layout is put forward which can be used to lay out the gateroad in the bottom slicing to hypo-high stress area relatively near the coal pillar. The problem of depressing mining benefit due to the bigger inboard distance can be improved by using the roof beam and side bolts. Reinforced concrete and concrete-filled steel tube beams are used in the technique of sparklet-inboard-type layout to increase the available height of gateroad. As a result，the problem of the deficient height of the gateroad in the bottom slicing is resolved.

The fault effect of strata displacement in underground engineering is studied. Through some preferred index，the preferred fault can be determined and the intensity of special strata displacement is forecasted by preferred index method. Finally，the cause of preferred fault effect of strata displacement is analyzed with preferred plane theory .

Granule failure of calcareous sand is very special at low stress level. The effect of confining pressure on granule farlure is analyzed and its deformation mechanism discussed. Further the coupling interaction of failure and slide is studied for calcareous sand. The interaction is described by damage model and bounding surface model，respectively. Computation shows that there is good agreement between numerical simulation and test results.

Under the condition of pumping water from the deep well point，the viscoelastic flow model in deep excavation is proposed to consider the three-dimensional deformation of the viscoelastic compaction of the soil skeleton of aquifer due to pumping and coupling influence of soil-water. Furthermore，on the basis of the model，numerical simulation with FEM is used. In order to improve computing precision，unsaturated zone and unconfined flow are taken into consideration. In addition，an object-oriented FEM software based on Microsoft Windows 95/98/NT is developed. The basic program frame and main codes are given.

According to the distribution regularity of axial force and frictional resisting force of cement treated composite foundation，the force acting on soft soil-cement soil pile is considered simply as two kinds of friction forces uniformly and triangularly acting along the pile. This result is well fitted to Mindlin solution for the given cases. As a result，a simple calculation method is put forward for engineering design estimation beforehand.

According to field investigation，research and analysis on surrounding environment condition，the hydraulic overflow problem of the foundation of an international container heap field in Hefei city，the splict problem of the Hefei Mosque，the internal scour problem of a market-house foundation in Shitai county，Anhui province，are discussed. It is thought that the rapid change of hydrogeological condition in site，and the erosion action by water level rising and descending on foundation are the major reasons for the above three problems. During a building’s constructing and using，the variation of natural condition and the effect of human being’s building action often rapidly change the engineering geological condition in site，and give rise to new engineering geological problems，such as the compression of foundation soil，ruffle of soil structure or filtration deformation. The rising of groundwater often makes foundation soil and cushion soften，strength fall or underconsolidated soil collapse. The descending of groundwater often makes hidden soil caves collapse，foundation settle or leads to internal scour. Geotechnique engineers should pay more and more attention to the problem of environment geology to keep engineering safe and stable and reduce the economic loss resulting from deterioration of enviroment.